Flavor asymmetry of polarized antiquark distributions and semi-inclusive DIS

The $1\mathrm{/}{N}_c$-expansion of QCD suggests large flavor asymmetries of the polarized antiquark distributions in the nucleon. This is confirmed by model calculations in the large-$N_c$ limit (chiral quark-soliton model), which give sizable results for $\mathrm{\Delta }\bar{u}(x)-\mathrm{\Delta }\bar{d}(x)$ and $\Delta\bar u (x)

• \Delta\bar d (x) - 2 \Delta \bar s (x)$. We compute the contributions of these flavor asymmetries to the spin asymmetries in hadron production in semi-inclusive deep-inelastic scattering. We show that the large flavor asymmetries predicted by the chiral quark-soliton model are consistent with the recent HERMES data for spin asymmetries in charged hadron production.